There was a group of adolescents (15-20 of them) who were with 1 or 2 elders. They did not adhere to the seat belt signs and it was mentioned to the cabin crew they didn’t appear to want to address it. Although there was one message over the PA system. Maybe it should have been the elders to control their charges. But someone should have. Another passenger said that he had been on more well behaved stag parties.